SU767964A1 - Device for analog-digital converter - Google Patents

Description

(54) DEVICE FOR ANALOG-DIGITAL

one

The invention relates to systems for automatically converting an analog value to a discrete electrical signal, namely, to analog-to-digital converters.

A functional analog-to-digital converter is known, which contains a precise-reference functional converter and a rough-reference functional converter, the analog inputs of which are connected to the synchronization voltage of the exact and rough samples, the adder, the channel selector, the first control unit, the output of which is controlled by the first generator connected to the input of the reverse of the first reversible counter, the digital output of which is connected to the digital input of the precision readout converter 1.

A disadvantage of the known device is the complexity of the exact and coarse sample interface circuitry due to the presence of a digital adder and a channel selector, the construction scheme of which is complicated when the number of samples is more than two. CONVERSIONS

The closest in technical essence to the proposed device is an analog-to-digital conversion device containing functional converters of coarse and precise samples, the outputs of which are connected to phase detectors, controlled generators, whose inputs are connected to the outputs of the corresponding phase detectors, one output of the first controlled generator is connected to the input of the reverse of the first reverse counter, 0 ka, the outputs of the second control of the generator are connected to the counting input and the input, reverse to Second reversing counter 2.

The disadvantage of this device is that the presence of parasitic amplitude and phase modulations removed from multiphase functional transducers leads to a tracking system error and the analog-code converter as a whole.

The purpose of the invention is to increase the accuracy of the device for analog-to-digital conversion.

The goal is achieved due to the fact that a code matching unit is inserted into the device for analog-digital conversion, the input of which is connected to the second

the output of the first controlled oscillator, and the output with the counting input of the first reversible counter, the digital outputs of which are connected to the digital inputs of the coarse reference function transducer, the digital outputs of the second reversible counter connected to the inputs of the precision reference function converter.

The drawing shows a block diagram of the device.

The device for analog-to-digital conversion contains a functional converter of coarse reference 1, a functional converter of accurate reference 2, phase detectors 3 and 4, controlled generators 5 and 6, a block 7 for code matching, reversible counters 8 and 9. Functional converters 1 and 2 are connected through phase detectors 3, 4 to controllable generators 5 and 6, which in turn are associated with reversible counters 8 and .9.

A functional converter 1 comparing the synchronization voltages of the coarse readout and the test angle of the reversing counter 8 generates the co-channel voltage mismatch.

The functional converter 2, by comparing the synchronization voltage of the exact reference and the test angle of the reversible counter 9, generates a voltage for matching the exact channel. Phase detectors 3 and 4 also contain low-pass filters, demodulate the error voltages, and determine the counting direction of the reversible counters 8 and 9. The oscillators 5, 6 controlled by the voltage generate pulses, the frequency of which is proportional to the value of the control voltages, and provide the transmission of counting direction signals from phase detectors 3 and 4 to reversible counters 8 and 9. The code matching unit 7 serves to interface to the high bits of the reversing counter 8 with the lower bits of the reverse ivnogo counter 9. A reversible counter 8 generates a high bits of the code rough rotation angle of the shaft frame. The up / down counter 9 forms the most significant bits of the angle of rotation code, the exact reading shaft.

The device works as follows.

The synchronization voltages of the coarse and accurate readings are fed to the corresponding analog inputs of the functional transducers I and 2, the digital inputs of which pass the test code values from the reversible counter 8 and the test angle from the reversible counter 9.

As a result, voltages are generated at the output of functional converters 1 and 2, which are demodulated by phase detectors 3 and 4, as a result of which control voltages are generated, which, acting on controlled generators 5 and 6, regulate the clock frequency and reverse of counters 8 and 9 This ultimately leads to the fact that the code values are angularly (,. and dL coincide with the values of the angles of rotation of the shafts of the coarse and accurate readings 0, and Q, respectively, i.e. the tracking mode is carried out.

Block 7 is used to match the code values of the coarse and exact samples (reversible counters 8 and 9). Block 7 of code matching is a variable multiplication unit. This block in the device includes a driver, a W-bit counter and an OR element. The required multiplication factor of the stake matching unit 7 is determined from the condition that the low-order bit of the reversible counter 8 is next after the high bit of the reversible counter 9, i.e. the counter 8 is a continuation of the counter 9. This condition is fulfilled depending on the reduction coefficient between the shaft of the coarse and accurate readings and the selection of the appropriate number of bits B counters of the coarse and exact

 readings that form the value of the angle of rotation of the shaft.

The use of a block, matching the codes in the device for analog-to-digital conversion, provides for the construction of standard channels of analog-to-digital converters in multi-channel systems of increased accuracy.

The device may simply redistribute the angle code bits, which are removed from the coarse and accurate counters. For example, instead of five rough count bits and seven precision count bits, you can select ten precision count bits and three rough count bits without changing the basic connections of the device.

The economic effect from the use of the proposed technical solution is due to the indicated technical advantages.

Claims (2)

1. US patent number 3508252, cl. 340-347, 1971. 2. Zverev A. E. and others. Converters of angular displacements into a digital code. . M., “Energie, 1974. p. 82